Which epidermal cells act as immune sentinels by presenting antigens?

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Multiple Choice

Which epidermal cells act as immune sentinels by presenting antigens?

The immune sentinels in the epidermis are Langerhans cells. These are specialized dendritic cells that patrol the skin, sampling any foreign material that breaches the barrier. They take up antigens, process them, and then migrate to nearby lymph nodes to present peptide fragments on MHC class II molecules to CD4+ T cells, providing the necessary co-stimulatory signals to activate the adaptive immune response. This sentinel role is what distinguishes them from other epidermal cells. Keratinocytes mainly form the physical barrier and can present some antigens under inflammatory conditions, but they aren’t the primary antigen-presenting sentinels. Melanocytes produce pigment, and adipocytes reside deeper in subcutaneous tissue, not in the epidermis, so they aren’t the ones presenting skin antigens.

The immune sentinels in the epidermis are Langerhans cells. These are specialized dendritic cells that patrol the skin, sampling any foreign material that breaches the barrier. They take up antigens, process them, and then migrate to nearby lymph nodes to present peptide fragments on MHC class II molecules to CD4+ T cells, providing the necessary co-stimulatory signals to activate the adaptive immune response. This sentinel role is what distinguishes them from other epidermal cells.

Keratinocytes mainly form the physical barrier and can present some antigens under inflammatory conditions, but they aren’t the primary antigen-presenting sentinels. Melanocytes produce pigment, and adipocytes reside deeper in subcutaneous tissue, not in the epidermis, so they aren’t the ones presenting skin antigens.

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